In order to meet the ever growing demand for data services, the 3rd Generation Partnership Project (3GPP) Release 5 has introduced HSDPA techniques, so as to improve downlink data transmission rate. The HSDPA techniques are applicable to Wideband Code Division Multiple Access Frequency Division Duplex (WCDMA FDD), Universal Terrestrial Radio Access Time Division Duplex (UTRA TDD), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) schemes. Viewed from the technical standpoint, HSDPA is mainly implemented by introducing a High Speed Downlink Shared Channel (HS-DSCH) to enhance the air interface and adding corresponding function entities in a Universal Terrestrial Radio Access Network (UTRAN); viewed from the under-layer aspect, it is mainly implemented by introducing the Adaptive Modulation and Coding (AMC) and Hybrid Automatic Repeat reQuest (HARQ) techniques to increase the data throughput; and viewed from the overall architecture, it is mainly implemented by introducing a new Media Access Control Entity (MAC-hs) at the Media Access Control (MAC) layer of a base station (NodeB) to specially accomplish processing of parameters related to HS-DSCHs and of the HARQ protocol and adding relevant operating signaling at the higher layer and interfaces, so as to enhance the processing capability of the NodeB.
FIG. 1 shows a MAC-hs model at the UTRAN side. This entity is located at a NodeB, and comprises the following functional modules: a flow control module, a scheduling and priority handling module, an HARQ module, and a Transmission Format and Resource Combination (TFRC) selection module.
The data processing procedures (data transmission procedures) of the MAC-hs at the UTRAN side are as follows.
The higher layer transmits data via an Iub interface (an interface between the NodeB and a Radio Network Controller (RNC)) to the MAC-hs at the NodeB, in accordance with the capacity allocated by the MAC-hs flow control module.
The scheduling and priority handling module stores the data into a corresponding priority queue, in accordance with a mapping relationship configured by the higher layer when the connection is established.
The scheduling and priority handling module determines a priority queue to be scheduled, and determines whether to transmit new data or retransmit failed data.
The scheduling and priority handling module assembles a number of MAC-hs Service Data Units (SDUs) in the scheduled priority queue into a MAC-hs Protocol Data Unit (PDU), and determines its Queue Identifier (Queue ID) and Transmission Sequence Number (TSN). The MAC-hs PDUs from different priority queues are numbered separately; the initial value of a TSN is 0; for each queue, each time a new MAC-hs PDU is transmitted, the TSN is incremented by 1.
The scheduling and priority handling module submits the assembled MAC-hs PDU to the HARQ module, and notifies the HARQ module of the corresponding Queue ID and TSN.
The HARQ module selects an appropriate HARQ process to transmit the MAC-hs PDU, and sets the Queue ID and TSN therein.
The TFRC selection module selects an appropriate modulation and coding scheme, notifies the physical layer of the modulation and coding scheme, and submits the MAC-hs PDU to the physical layer. The physical layer notifies the User Equipment (UE) of the modulation scheme and the transmission block size through a High Speed Shared Control Channel (HS-SCCH), and transmits the MAC-hs PDU to the UE over a High Speed Physical Downlink Shared Channel (HS-PDSCH).
FIG. 2 shows a MAC-hs model at the UE side, which comprises the following functional modules: an HARQ module, a reordering queue distribution module, a reordering module, and a disassembly module.
The data processing procedures (data receiving procedures) of the MAC-hs at the UE side are as follows.
The HARQ module determines the HARQ process that is used to transmit the MAC-hs PDU currently and whether the data is new data or retransmitted data, in accordance with the information carried on the control channel.
If the data is new data, the HARQ module decodes the data and judges whether the data is received correctly. If the data is received correctly, it generates an Acknowledgement (ACK) message, and submits the data to the reordering queue distribution module. If the data is not received correctly, it generates a Non-Acknowledgement (NACK) message, and stores the failed data. The ACK or NACK message is fed back over the control channel to the UTRAN side for processing.
If the data is retransmitted data, the HARQ module combines the retransmitted data with the failed data, and then judge whether the data can be decoded correctly. If the data can be decoded correctly, the HARQ module generates an ACK message, and submits the data to the reordering queue distribution module. If the data can not be decoded correctly, the HARQ module generates a NACK message, and stores the combined data. The ACK or NACK message is fed back over the control channel to the UTRAN side for processing.
The reordering queue distribution module distributes the received MAC-hs PDU to a corresponding reordering buffer in accordance with the queue ID in the MAC-hs PDU.
The reordering module processes the data in the reordering buffer, and judges whether the data is received in sequence in accordance with the TSN in the MAC-hs PDU. If the data is received in sequence, the reordering module submits the MAC-hs PDU to the disassembly module. If the data is not received in sequence, it keeps the data in the buffer temporarily, and submits the MAC-hs PDU after all other MAC-hs PDUs with TSNs smaller than the TSN of the MAC-hs PDU have been received in sequence.
The disassembly module removes the header information and possible padding bits from the received MAC-hs PDU, and sends the MAC-d PDU contained in the MAC-hs PDU to a corresponding MAC-d entity.
The implementing method for a radio network or UE in the prior art is mainly proposed for single-carrier HSDPA, and therefore is inconvenient in managing and scheduling multi-carrier resources. For any UE, in each Transmission Time Interval (TTI) for the existing model, only one MAC-hs PDU from a priority queue is permitted to be transmitted, and only one HARQ entity is established for each UE at the UTRAN side. Therefore, if there are multiple carriers used to support HSDPA in a logic cell, the implementing method for a wireless network or UE in the prior art would not be able to meet the demand for multi-carrier HSDPA.